1. Field of the Invention
The present invention relates to a vehicle seat slide device.
2. Description of Related Art
There is such a vehicle seat slide device in which a rail drive mechanism is provided between a lower rail and an upper rail constituting a seat slide rail. The rail drive mechanism is configured to move the upper rail relative to the lower rail based on a driving force of a motor.
For example, a seat slide device described in Japanese Patent Application Publication No. 2008-265735 (JP 2008-265735 A) includes a transfer shaft rotationally driven by motor drive in a state where the transfer shaft is provided in a bridging manner between a pair of right and left seat slide rails. Further, in the seat slide device, a rail drive mechanism provided in each of the seat slide rails includes a screw shaft extending in an extension direction of the each of the seat slide rails, a nut member threadedly engaged with the screw shaft, and a rotation transmission mechanism that rotates the screw shaft and the nut member relative to each other based on a driving force transmitted from a motor via the transfer shaft. More specifically, in this conventional example, the nut member and the screw shaft are rotationally driven in a state where the nut member is fixed to one of the lower rail and the upper rail, and the screw shaft is supported by the other one of the lower rail and the upper rail. Hereby, the upper rail supported by the lower rail is moved forward and backward based on a threaded engagement relationship (screw pair) between the screw shaft and the nut member.